The speakers do have an impedance curve that goes down to 4 ohms or so, which shouldn't be a problem for the Parasound. That said, the Triton 2 apparently have a power rating of up to 500 watts.
I am not sure what thin sounding entails. This description seems to be popular these days around here, can someone throw me a bone?
Other than that, I really don't think it's the amp, especially at that volume level. But if the OP really wants one, since the speakers can handle 500 watts, moving up to separates might be a thought.